After you are married, either party to the marriage is able to change their name to that of their spouse simply by providing the official marriage certificate as evidence of the marriage.
The marriage certificate you received as part of your ceremony is simply commemorative.
You can change your name at any time after the marriage has taken place, whether that be days or years later.
Below are some links to info and documents to help you change your name.
Here are some links you’ll likely need:
- RMS/Drivers Licence & Registration
- Australian Passport Office
- Australian Tax Office
- Australian Electoral Commission
- Medicare Australia
Good luck!